Oxygen breathing devices are used in a variety of applications where it is required to provide oxygen as singular or supplementary oxygen source to a person. A typical application of such oxygen breathing devices is the emergency oxygen supply system in aircraft provided to passengers or crew members in case of sudden pressure drop or any other emergency where the ambient air condition within the aircraft is negatively affected.
Generally, such oxygen breathing devices comprise an oxygen source like a compressed oxygen tank or chemical oxygen source, an oxygen supply line like an oxygen tube or a flexible oxygen hose for directing a flow of oxygen from the oxygen source to the person to be supplied with oxygen and a pressure regulator for controlling the flow of oxygen from the oxygen source to the person. The oxygen may be provided to the person via an opening arranged close to the mouth or nose of the person or an oxygen mask which can be fixed to the person in such a way that the mouth and/or the nose are covered to define an interior space in front of the mouth and/or nose. Such an interior space can then be provided with a continuous or discontinuous flow of oxygen.
A general problem associated with such oxygen breathing devices lies in the desire to construct such devices lightweight and small but to be able to supply a person for a long period of time with oxygen using the device.
EP 08151600 discloses a chemical oxygen breathing device for long time supply of a person, the device comprising two chemical oxygen generators supplying the person sequentially with oxygen. Such oxygen breathing device will significantly improve the efficiency of oxygen supply and the duration of such supply by reducing the total weight and dimension of the device at the same time. However, it is desirable to further increase the duration of oxygen supply and to further reduce the weight and dimension of such oxygen breathing devices.
EP 08151305 discloses an oxygen breathing device having a self-sustaining energy system. Such device will significantly reduce overall weight of an oxygen supply system within an aircraft and thus allow to provide oxygen sources having more oxygen capacity without increasing the weight of the system in total. However, it is desirable to further improve such oxygen supply systems in order to further reduce the weight and dimension and to further increase the duration of oxygen supply.